In situations where encrypted information (i.e., ciphertext) is permanently available to the public, an attacker motivated to decrypt the ciphertext may have practically unlimited time and resources to attempt decryption offline, without detection. Legitimate interested parties (i.e., creators and intended recipients of ciphertext) thus could not know specifically that the attacker is accessing or trying to decrypt the ciphertext, such as by cryptanalysis or brute force, and take reactive measures to protect against such attacks. Ciphertext on a blockchain is a common situation like this, with ciphertext concealing private transactions.
Although known workarounds exist, such as avoidance of publicly sharing cryptographically verifiable data in a distributed public ledger, other pitfalls abound. Privately maintaining consistent records of transactions, while protecting against data breaches, leaks, forgeries, destruction, tampering, or accidental loss, may incur additional expenses and difficulties, which may be remedied by adoption of blockchain technology.
In order to ensure adoption of technology that would result in private information being permanently and publicly available, potential adopters typically want assurances that information of their private transactions will be reasonably secure despite allowing potential attackers unfettered access to such confidential information, even if only in encrypted form. In these situations, while established good practices such as key rotation, strong algorithms, long keys, etc., should generally be used, these practices alone would not be sufficient to provide reasonable safeguards for sensitive encrypted information that would be publicly available on a permanent public ledger, for example, or in any other persistent public forum, because information may not be removed or altered to use new encryption keys or schemes.
Trends of continued evolution of computing platforms, capable of breaking even strong encryption, generally signify that encryption that is considered strong now will not be strong decades into the future, even if confidentiality will need to be maintained for substantially longer time periods, if not indefinitely. An added level of assurance is therefore needed in order to protect private information and to instill confidence into potential adopters of public platforms, e.g., blockchain-based systems, for private transactions and other sensitive information, in situations where data integrity and confidentiality are highly valued.
In the drawings, like reference numbers generally indicate identical or similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.